The first part of the article (Sect. 1–6), an earlier version of which appeared in 1964, constitutes a survey of medieval Arabic lexicography, which resulted in the conlusion that the works of these lexicographers could not be used, according to modern standards, as primary sources for lexical studies of Arabic, as has frequently been done up to now. It is characteristic of medieval Arabic lexicography that it was limited to the study of Classical Arabic, the literary language of Islamic society until the end of the tenth century. The beginnings of Arabic lexicography date back to the time of ‘Alī or to the early Umayyads and were motivated by the concern for the classical language and its preservation from decline and deterioration. It was primarily the Koran, tradition literature, early poetry and proverbs which served as a basis for lexical studies. As a result of these scholarly efforts a number of lexical works were produced, some of which aiming at a complete vocabulary of the language, others being limited to certain linguistic and literary fields. Besides dictionaries in the proper sense there are also onomastic dictionaries. The arrangement of roots varies in different works. Although some of these dictionaries are extremely voluminous, they do not adequately represent the actual state of the language, as evidenced by the Lisān al-’Arab, for, on the one hand, they are often incomplete, on the other hand they contain material of dubious origin. Information as to usage and currency is lacking. The arrangement of the material within the roots is irregular and unsystematic, and the morphological structure of words is not always clearly established. There are shortcomings with regard to the definition of word meaning; moreover, no distinction is made between common and occasional meaning. Sometimes a meaning is stated as being known, sometimes it is defined by synonyms. Information regarding gender is often too general and wide, whereas with regard to meaning it is too narrow, based on isolated occurrences or simply false. In conclusion, reference is made to the Wörterbuch der klassischen arabischen Sprache (WKAS), which constitutes a new approach to Arabic lexicography.

The second part of the paper (Sect.7–10) reports on the progress and development of the WKAS up to 1983 (date of publication of the first half of the second volume). The source material has been considerably enlarged, and there are also improvements from the technical point of view. Another change, however, is the widening of the linguistic scope. In addition to the classical language in the strict sense, translations from Greek (and Syriac) and relevant works succeeding them are taken into acount. Although this material only refers to certain domains of Greek thought, mainly pertaining to scientific subjects, it is rather heterogenous and often requires considerable expert knowledge. Theoretical concepts are more frequent here than in common literary language. The translations vary, moreover, as to quality and usage; the latter also applies to relevant subsequent literature. In philosophy, for instance, only a small quantity of loan-words and foreign words is to be observed. Word composition being almost completely lacking as a means of translation, Greek terms were rendered by way of morphological derivations and syntactical structures, or by semantic extensions and semantic loans. At the present stage of research it is not yet possible to achieve a complete inventory of technical terms; consequently, examples quoted as reference are not always equally pertinent. For the same reason a number of terms and definitions could be added in the field of philosophy as well. Another problem is the choice of adequate European meanings for rendering Arabic concepts. In the WKAS philosophical terms are partially included in the entries devoted to common language. In such cases, but also when they are treated apart, sequences of meaning are sometimes produced which are neither homogeneous in themselves, nor do they always fit in with the examples quoted. Thus the user must take notice of the distinction made within individual entries, and, if required, rely on his own judgment in finding further definitions. All things considered, the WKAS is certainly not to be regarded as a substitute for a dictionary of philosophical terms, but it offers rich and valuable material in this respect.